2-Thioorotic acid 2-Thiouracil-4-carboxylic acid 4-Pyrimidinecarboxylic acid, 1,2,3,6-tetrahydro-6-oxo-2-thioxo- 6-Carboxy-2-thiouracil 6953-78-2 Mercaptoorotic acid NSC39961 Orotic acid, 2-thio-